Whose Bible is bigger? Obama's or Biden's?

U.S. Supreme Court Chief Justice John Roberts administers the oath of office to President Barack Obama as first lady Michelle Obama and daughters Malia and Sasha look on during ceremonies on the West front of the U.S Capitol in Washington, D.C. on Jan. 21.

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Vice President Joe Biden is sworn-in as his wife Jill holds the Biden Family Bible during the 57th Presidential Inauguration ceremonial swearing-in at the U.S. Capitol on Jan. 21.

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President Barack Obama speaks after taking the oath of office at the U.S. Capitol on Jan. 21 in Washington, D.C.

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President Barack Obama takes the oath of office using a Bible that belonged to the Rev. Martin Luther King Jr. in front of First Lady Michelle Obama during the 57th Presidential Inauguration ceremonial swearing-in.

President Barack Obama and Vice President Joe Biden took their respective oaths of office upon Bibles unique to each man.

Obama honored slain civil rights leader, Martin Luther King, Jr. by using one of Dr. King’s Bibles along with the Bible used by President Lincoln in his first Inauguration on March 4, 1861.

Biden was sworn in using his family Bible, which is five inches thick and has been in the Biden family since 1893. He has used it every time he was sworn in as a U.S. Senator and when he was sworn in as Vice President in 2009.